1. Field of the Invention
The present invention relates to a sheet feed apparatus and a recording apparatus which is equipped with the sheet feed apparatus. More particularly, the present invention relates to the sheet feed apparatus which separates sheets stacked on a sheet stacking means one by one and transports the separated sheets to an image recording unit, and the recording apparatus which is equipped with this sheet feed apparatus.
2. Related Background Art
Conventionally, a recording apparatus such as a printer, a copying machine, a facsimile machine or the like is ordinarily equipped with a sheet feed apparatus which feeds sheets to an image recording unit. As such the sheet feed apparatus, there is the structure that an inclined plane member is provided at the end on the downstream side of a sheet feed direction of a sheet stacking means, and the inclined plane member is set to come into contact with the sheets fed by a sheet feed means, whereby the sheet is separated one by one.
FIG. 22 is a schematic diagram showing the conventional sheet feed apparatus which applies a system of separating the sheet by using such the inclined plane member. In FIG. 22, numeral 215 denotes a sheet feed roller which acts as the sheet feed means, and numeral 214 denotes a sheet feed arm which rotatably holds the sheet feed roller 215 at its end and which is also rotatably held by an arm shaft 214a. 
Numeral 210 denotes a sheet feed cassette which acts as the sheet stacking means on which sheets (or recording paper) P are stacked, and numeral 219 denotes an inclined plane member which comes into contact with the sheets P fed by the rotation of the sheet feed roller 215 and is thus used to separate the sheets P one by one. The inclined plane member 219 is provided at the end on the downstream side of the sheet feed direction of the sheet feed cassette 210.
Then, an uppermost recording sheet P1 fed by the sheet feed roller 215 is separated from the sheets P by the inclined plane member 219, and then transported to a not-shown image recording unit through a sheet transportation path R. At this time, it is desirable to set the height of the inclined plane member 219 high so that the sheet P1 fed by the sheet feed roller 215 passes the sheet transportation path R as it changes the direction upward along the inclined plane member 219.
Incidentally, in such the conventional sheet feed apparatus and the recording apparatus equipped with it, the sheet feed cassette 210 is detachably installed in the main body of the apparatus. If the sheet feed roller 215 comes into contact with the sheet feed cassette 210 when the cassette 210 is installed and released, the sheet feed roller 215 and the sheet feed cassette 210 might be damaged, whereby it is necessary to limit the height of the sheet feed cassette 210, and thus the height of the inclined plane member 219 is limited.
However, if the height of the inclined plane member 219 is limited as above, the sheet P1 fed by the sheet feed roller 215 passes the sheet transportation path R as it changes the direction upward along the inclined plane member 219 when the number of the sheets P stacked on the sheet feed cassette 210 is small. However, when the number of the sheets P stacked on the sheet feed cassette 210 is large, since the sheets P do not so change the direction even if the sheets P come into contact with the inclined plane member 219, the sheets P come into contact with a guide 220 constituting the sheet transportation path R at a sharp angle.
Then, if the sheets P come into contact with the guide 220 at such the sharp angle, the problems that the sheet can not be fed, the edge of the sheet is folded, and the like occur.
Further, there is a sheet feed apparatus which is equipped with a sheet stacking unit to stack the sheets thereon, a sheet feed unit to feed the sheets stacked on the sheet stacking unit to the downstream side of the sheet transportation direction, a sheet separation unit provided on the downstream side of the sheet stacking unit to separate the sheet fed from the sheet feed unit, and a sheet turnabout path to convert and guide the transportation direction of the sheet fed from the sheet stacking unit.
The sheet feed unit pushes the sheets on the sheet stacking unit against the sheet separation unit as feeding them, separates the sheets one by one, and then feeds the separated sheets to the sheet turnabout path. The sheet turnabout path guides the sheet, e.g., by ax making U-turn, to an image recording unit.
The purpose of U-turn transporting the sheet is to deal with the miniaturization by arranging the image recording unit above the sheet stacking unit to shorten the horizontal dimensions of the image recording unit and reduce the setup area of the recording apparatus.
However, if the sheet is U-turn transported like this, the problem that the height of the recording apparatus increases because the height of the sheet feed apparatus increases occurs.
An object of the present invention is to provide a sheet feed apparatus in/from which a sheet feed cassette can be installed/released without any contact with a sheet feed roller, and which can surely feed sheets without any fold of their edges, and a recording apparatus which is equipped with this sheet feed apparatus.
Another object of the present invention is to provide a sheet feed apparatus of which the height is low, and a recording apparatus which is equipped with this sheet feed apparatus.
Still another object of the present invention is to provide a sheet feed apparatus comprising: a sheet stacking means, being able to be installed in and released from the main body of the apparatus, for stacking sheets; a sheet feed roller for feeding the sheets stacked on the sheet stacking means; and plural inclined plane members, disposed at the end of the downstream side of a sheet feed direction of the sheet stacking means, for coming into contact with the sheets fed by the sheet feed roller to separate them, wherein, among the plural inclined plane members, the height of the inclined plane member corresponding to the sheet feed roller is set to be lower than the height of the other inclined plane members.
Still another object of the present invention is to provide a sheet feed apparatus comprising: a sheet stacking means for stacking sheets; a sheet feed roller for feeding the sheets stacked on the sheet stacking means; plural inclined plane members, disposed at the end of the downstream side of a sheet feed direction of the sheet stacking means, for coming into contact with the sheets fed by the sheet feed roller to separate them; and a reversal roller for reversing the sheet fed by the sheet feed roller, wherein the reversal roller has plural roller units, and each of the plural roller units is disposed between the inclined plane members in a sheet width direction.